This invention relates to an apparatus and method for separating oil and water, and more particularly, to a mobile oil-water separator which can be transported to a site for use. The term oil-water as use herein is intended to cover a wide range of immiscible liquids and lightweight solids. In general, the invention is applicable to the separation of immiscible liquids of different specific gravities and lightweight solids that are therefore susceptible to gravity separation.
Several approaches have been proposed for gravitationally separating oil and other materials from a liquid influent stream. Such apparatuses are installed both underground and aboveground and are adapted for oil-water runoff from rain or hose downs at gasoline service stations, truck stops, parking lots, shopping mall areas and the like. Such known apparatuses have not been completely satisfactory, mainly due to the difficulties associated with the frequent cleaning and maintenance due to clogging of the apparatus with oil and solids and the inability of the apparatus to adequately separate the immiscible liquids and solids while still maintaining a relatively compact size.
The typical method for removing liquid particles and large solid materials suspended in liquid (e.g. water) is to allow gravity, time, and distance to allow the materials to fall out of the influent stream. However, for this method to be fully effective the tank must be large enough to allow the materials sufficient time to settle out and with most compact tanks, there is not sufficient time for gravity to serve as the primary means for removal of solids. None of the prior art devices provide an effective means for separating immiscible liquids and solids from an influent stream in a compact and mobile unit requiring relatively infrequent maintenance and cleaning.